1. Field of the Invention
The present invention relates to personal communication services systems, and more particularly to an apparatus and method for managing a status and alarm message and for broadcasting system time in a global positioning system receiver.
2. Description of the Related Art
FIG. 1 illustrates a personal communication services (PCS) system. The PCS system includes a plurality of Gateway Communication Interconnection Networks (GCINs) and, a plurality of link paths formed between Mobile Switching Centers (MSCs). Since, the PCS system does not have link paths formed directly between the GCINs, it may not be possible to provide an inter-process communication (IPC) between the GCINs. Accordingly, for a hand-off or exchange of data between the GCINs, the PCS system uses a hard hand-off path between the MSCs. However, this hand-off may generate an unavoidable call lag of over 100 msec. A Communication Interconnection Network (CIN), which includes the GCIN and Local Communication Interconnection Networks (LCINs), provides a packet data transmission path between a Base Station Transceiver Subsystem (BTS) and a Base Station Controller (BSC) to transfer data and signals through the CIN.
FIG. 2 illustrates a block diagram of a device for broadcasting Time of Date (TOD) message data from a global positioning system receiver (GPSR) according to the prior art. As illustrated, in a conventional Code Division Multiple Access (CDMA) system, Time and Frequency Processors (TFPs) 4-1 and 4-2 on a Time and Frequency Controller Assembly (TFCA) board receive TOD message data from GPSRs 2-1 and 2-2.
The TOD message data from GPSRs 2-1 and 2-2 is commonly composed of 16 bytes of information, where 11-bytes represent the system time, 1-byte represents the status of the GPSR, 1-byte represents an alarm of the GPSR, 2-bytes represent a leap second, and 1-byte represents the end of the message. The system time includes the year, month, day, hour, minute and second. The TFPs 4-1 and 4-2 manage and report the status and the alarms of GPSRs 2-1 and 2-2 based on the received TOD message data. The TFPs 4-1 and 4-2 also calculate the system time in units of seconds to broadcast the calculated system time to respective processors in BTS 10 through a High Capacity IPC Node Board Assembly (HINA). The BTS 10 includes GPSRs 2-1 and 2-2, TFPs 4-1 and 4-2, and BTS Control Processors (BCPs) 6-1 and 6-2. A Call Control Processor (CCP) 8 belonging to the BSC is connected to BTS 10 to control a call.
In the PCS system which is significantly modified from the conventional CDMA system, software for processing the TOD message data is also modified. The dotted line terminating at an arrow at each end in FIG. 2 represents the synchronization of GPSRs 2-1 and 2-2 for the PCS system. The TFPs 4-1 and 4-2 on the TFCA board receive a 10 MHz unit clock of 1 Pulse Per Second (1 PPS) for generating a system clock which is supplied to designated boards. The TFPs 4-1 and 4-2 also process the TOD message data.
However, the TFPs cannot report in detail the status and the alarm of the GPSR. The conventional method of managing the status and the alarm of the GPSRs is unnecessarily complex and time consuming. Also, the system time should be calculated from the TOD message data. Since the TFPs on the TFCA board manage the status and the alarm of the GPSR, the TFPs should also manage the associated clocks and the status and the alarm of the TFCA board itself to simplify the process. In addition, since software in the TFCA board is instrumental in generating and managing the clocks used in the system, it is difficult to effectively manage and control the clocks. This is because the synchronization of the GPSRs (when initialized) is controlled by software in the TFCA board, while generation and distribution of the clocks is processed by hardware within the TFCA board.